Lessons learned is a research area that focuses on identifying, documenting, and analyzing the experiences gained from projects, programs, or initiatives in order to improve future decision-making and performance. This process typically involves reflecting on successes and failures, evaluating what worked well and what could have been done better, and recording key insights and recommendations for future reference. Lessons learned research helps organizations and individuals avoid repeating past mistakes, capitalize on best practices, and continuously improve their performance and outcomes. It is often used in project management, organizational learning, and knowledge management settings.